Bi-directional stepping mechanism



Dec. 20, 1966 J. H, DRILLICK 3, 9 3

El -DIRECTIONAL STEPPING MECHANISM Filed July 14, 1964 Q I 4 Sheets-Sheet IL INVENTOR. g JACOB H. DRILLICK A TTORNEYS.

4 Sheets-Sheet 2 J. H DRILLICK BIZ-DIRECTIONAL STEPPING MECHANISM Dec. 20, 1966 Filed July 14, 1964 m M W H T m N Dec. 20, 1966 J. H. DRILLICK 3,292,832

BI-DIRECTIONAL STEPPING MECHANISM Filed July 14, 1964 4 Sheets-Sheet 5 m 3 FIG.4

D Q 0 7 INVENTOR.

o 0 JACQB H. DRILLICK 0 53 0 BY awn/Z4 zd/M' A TTORNEYS.

Dec. 20, 1966 H. DRILUCK 3,292,832

BI-DIREC'IIONAL STEPPING MECHANISM Filed July 14, 1964 4 Sheets-Sheet 4 N g a 5% a F2 F2 I Q G 5? Fr 8 m m m (JO 0 O O O (J (D O 00 CO0 O O OO O FIG. 6

INVENTOR JACOB H. DRILLICK A TTORNE Y3.

United States PatentO 3,292,832 BI-DIRECTIONAL STEPPING MECHANI SM Jacob H. Drillick, South Hackensack, N.J., asslgnor to Ohr-Tronics, Inc., New York, N.Y., a corporation of New York Filed July 14, 1964, Ser. No. 382,564 Claims. (Cl. 226-49) This invention relates to a novel bi-direction-al stepping mechanism. More particularly, this invention contemplates a novel bi-directional stepping device for moving perforated tape through a sensing mechanism.

In the past, uni-directional stepping drives have been utilized to move tape past :a sensing mechanism.

Some of these drives have operated by using a ratchet and pawl assembly to either directly or indirectly motivate the tape past the sensing device.

The direct drive systems envision the use of the combination of an armature, ratchet wheel and pawl. The ratchet wheel is rotated by the'direct movement of the armature, to which the pawl is attached, toward an electromagnet when the electromagnet is energized.

This movement is highly undesirable since the motion of the armature is too instantaneous, swift and abrupt toward the electromagnet. Accordingly, the ratchet wheel is subjected to correspondingly sharp and high velocities. This would undoubtedly result in the ratchet Wheel overshooting the step-by-step sequence needed to read the individual perforations in the tape. Furthermore, the pawl and ratchet wheel would be subjected to excessive wear.

Some uni-directional indirect drive systems have also been constructed which rotate the ratchet wheel when the current, through the electromagnet, is interrupted or, in other words, when the electromagnet is de-energized. This latter technique. enables the pawl to rotate the ratchet wheel as the armature, to which the pawl is attached, relaxes to a position away from the electromagnet.

The indirect drive system is highly advantageous, since the tape is stepped on the movement of the armature away from the electromagnet. course, at a lower velocity. Also, it is desirable to step the tape on the interruption of the electromagnetic driving pulse, since this simplifies the control logic circuitry of the system. Heretofore, no direct bi-directional driving mechanisms have been conceived.

The movement of the tape bi-directionally'through a tape reader is desirous for numerous reasons. One reason is that it might be advantageous for the operator during the operation of the tape reader to repeat the reading of certain tape section.

Many bi-directional tape driving systems have been constructed. However, they have not proved satisfactory since they are both complicated and cumbersome in design. One such system utilized the combination of a motor drive, differential gear assembly and a plurality of friction clutches so arranged that the tape may be moved bi-directionally through a sensing device. Such an assembly is highly undesirable since it may be subject to endless breakdowns, due to its complexity, thereby decreasing greatly the efiiciency of the apparatus.

This invention, on the other hand, contemplates a novel bi-directional stepping mechanism which may be adapted to be utilized in a tape reader in order to smoothly and efiiciently bi-directionally motivate the tape through a tape reader.

It envisions the use of a novel bi-directional drive which utilizes two pawl carrying members to rotate a ratchet wheel in opposite directions, each pawl carrying member also carrying a pawl depressor which acts to push the op- This movement is, of

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posing pawl out of engagement with the ratchet wheel while its own pawl drives the ratchet wheel.

More specifically, this novel invention includes a pair of electromagne-ts and a ratchet wheel mounted on a shaft between the electromaguets. An armature is positioned adjacent each of the electromagnets, and is spring urged away from its associated electromagnet. Each armature carries a pawl and pawl depressor. A means is provided for energizing each electromagnet to attract the armature toward the electromagnet, thereby storing energy in the armature spring, to cock the armature pawl, and to depress the opposing pawl away from the ratchet wheel. A means is also provided to de-energize the electromagnet, to rotate the ratchet wheel, and to allow the opposing pawl to re-eng age the ratchet Wheel and thereby also preventing overshooting.

Other features will become apparent from the consideration of the following description, taken in connection with the drawings wherein:

FIG. 1 is a top view of the novel invention;

FIG. 2 is a side-elevated view illustrating the driving mechanism of this invention;

FIG. 3 is a partial side-elevated view illustrating the invention as the armature is being moved in the direction indicated by arrow A;

FIG. 4 is a partial side-elevated view showing the invention after the ratchet wheel has been cocked;

FIG. 5 is a partial isometric view of sensing mechamsm;

FIG. 6 is a front elevated view of the invention partly in section along line 11 of FIG. 1; and

FIG. 7 is a view showing the circuitry of the invention.

The components of this invention are mounted on both sides of a rectangular frame 1. Extending through the frame 1, at approximately its center, is a shaft 2 which is adapted to rotate the bearings (not shown) located within the frame 1 and bracket 5. Secured to the shaft 2, on one side of the frame 1, are a pair of cap stans 3 and 4. Each capstan 3 and 4 carries a plurality of grooves 6 about its periphery.

Mounted between the capsta-ns 3 and 4, and also secured to the shaft, is a sprocket wheel 7.

Positioned immediately adjacent to the capstans and 4 are a plurality of arms 8 arranged side-by-side and pivoted about shaft 10 within the bracket 11. The bracket, in turn, is secured to the frame 1.

Also pivoted about the shaft 10 is a detent arm 12, which extends outwardly directly over the sprocket wheel 7.

One end of each of the arms 8 carriesa star wheel 13 which is adapted to ride in the grooves 6 of the capstans 3 and 4. The other end of each of the arms 8 is maintained up against a plurality of adjustable screws 14 by the upward force of one end of the bias spring wires 15. The other end of the bias spring wires 15 are held in plate 16. A series of rectangular contacts 17 communicate with each bias spring wire 15.

When the arms 8 are abutting up against the screws 14, the wires 15 are in communication with a plurality of con tact posts 18 which are screwed into an electrical terminal block 20 arranged above the bias spring wires 15. Both the terminal block 20 and the rectangular contacts 17 are electrically connected to a data handling system.

Secured side-by-side to the shaft 2, on the opposite side of the frame 1 from the capstans 3 and 4, is ratchet wheel 19. The. ratchet wheel 19 has two sets of teeth 21 and '21 arranged about its periphery. The two sets of teeth 21 and 21' face in the opposite directions.

Within close proximity to, and arranged on each side of the ratchet wheel 19, are a pair of solenoids 23 and a 'detent roller assembly, generally indicated by 30.

and 24'.

Piv-otally attached at one end to each solenoid housing 24ja-nd 24 is one of a pair of armatures 25 and 25'.

A compressible spring 26 is anchored,-at ,one of its ends, to each solenoid 23 and 23" and is attached to the upper end of the armatures 25 and 25".

The armatures 25 and 25 carry pawls 27 and 27', respectively, which extend outwardly therefrornand are adapted to engage the teeth 21 and 21' of the ratchet wheel 19. 1

From the armatures 25 and-25' there also extend a pair of pawl depressors 28 and 28. Each pawl depressor 28 and 28' is adapted to depress the'opposing pawls 27 and 27, respectively- Positioned immediately above said ratchet wheel 19 is The detent; assembly 30 comprises a roller 31 which is maintained in contact with the teeth 21' by the act-ion of bias spring '32.

Operably associated with the end of the armatures 25 and 25, and carrying the-pawls 27 and 27', are a pair of interrupter switches generally indicated by 33 and'33. =Each switch is similar in construction to the other and comprises a pair of metallic strips 34, arranged parallel with respect to each other but spaced'apart.

One end of eachstrip carries a contact point 35.

Positioned between the strips 34 is a nonconducting card 36 which is adapted to slide along the longitudinal axis of the strips 34.

The strips are so constructed that when the card 36 slides in the direction of the contact points 35, it abuts up against the strip shoulder 37. Movement further in the direction of the contact points by the card 36 causes the contact points 35, carried by each strip, to be separated from each other.

An aperture 38 extends through each card 36 so that the end of the armatures 25 and 25' may be adapted to fit therein.

The interrupter switches 33 and 33' are connected in series to the solenoids 23 and 23 and a power source .(not' shown) by means of electrical wires 40 for continuous self-stepping of the tape.

the car 36, is adapted to move the card in such a position r23. Each? solenoid is enclosed in solenoid housing 24 that the contact points 35 carried by each strip are periodically not in contact with each other.

FIG. Tillustrates diagrammatically the circuit con- Terminals 41 are the output from the individual star wheel contacts, while terminal 42 is the common input terminal. Situated between the input and output terminals, there are arranged the bias spring contact wires 15 which are adapted to engage the contact posts 18 of the invent-ion.

The power input terminals to the interrupter switches 33 and 33' are illustrated at 46 while the power output terminal is shown at 47.

Each interrupter switch 33 and 33 is connected electrically in series (not shown) to the electromagnet circuit which consists of an electromagnet 48, a diode 50, a Zener diode 51 and 'a variable resistance 5-2.

In the normal position of the invention, the armatures 25 and 25' are held away from the solenoids 23 and 23 through the urging of springs 26. The pawls 27 and 27 also fit into one tooth of each set of teeth 21 and 21', respectively. The pawl depressors 28 and 28' are, accordingly, not in contact with the pawls 27' and 27, respectively.

When it is desired to operate this invention, the perforated tape 53 is threaded over the sprocket wheel 7 and beneath the sensing arms 8.

'energiiz-ng of solenoid 23'.

' 4 Current is-supplied to the solenoid 23'. 'Ihiscauses the armature 25' to move towards the solenoid 23 by magnetic attraction. See FIGS. 3 and 4.

As the armature 25' is activated, it moves the pawl from its initial position under one tooth of the set of teeth 21' to the next adjacent tooth and simultaneously moves the card 36 toward the contact points 35. See arrow B in FIG. 3. i

The moment the pawl 27' moves under the next adjacent tooth, the movement of the card 36 towards the contact points is such that the card abuts up against the strip shoulder 37 and thus separates the contact points 35 from each other.

As the armature 25 moves towards the solenoid, the pawl depressor :28, attached thereto, depresses the pawl 27 of the opposing armature 25 and disengages it from the teeth 21.

The separation of the contact points 35 breaks the flow of current to the solenoid, thereby causing the solenoid to d e-energize. Accordingly, the stretched spring 26 restores the armature back away from the solenoid and moves the card 36 away from the shoulder 37 so that the contact points 35 again touch each other.

As the armature is moved away from the solenoid, the pawl 27 rotates the ratchet wheel 19 and, correspondingly, the shaft 2, clockwise. See FIGS. 2, 3 and 4.

The clockwise movement of the shaft 2 causes the capstans 3 and 4, and the sprocket wheel 7, to rotate and thus advance the perforated tape 53 incrementally into contact wit-h the star wheels 13 which sense the perforations in the tap-e.

The sensing operation is described as follows: As the tape passes over the capstans 3 and 4, the star wheels 13 of the sensing arms 8, ride on top of the tape. 'This rotates the sensing arms 8- about shaft 10 and moves the bias spring wires 15 downwardly, away from contact with the contact posts 18.

When the star wheels 13 drop into the perforations in the tape, the sensing arms 8 are rotated about shaft 10 by the bias spring wires 15 until the bias spring wires engage the contact posts 18. When this occurs, the circuit through the s nsing device is completed for reading.

The above-mentioned operation of the invention describes the movement of the tap-e in one direction by the This invention contemplates bi-directional movement of tape. Accordingly, if it is desired to move the tape in the reverse direction, solenoid 23 is energized instead of solenoid 23'. When this occurs, the armature 25, interrupter switch 33, pawl 27 and pawl depressor 28 operate in a similar manner as above described. But, since the pawl 27 engages the teeth 21 in an angular direction opposite to the teeth 21, the shaft 2 is motivated in .a counterclockwise direction.

An electromagnet has been described and illustrated as the particular mode chosen to activate the pawl carrying members. It is to be understood that any suitable mechanical actuating means may be substituted for the electromagnet and still accomplish the intended purpose of this novel bi-directional stepping mechanism.

Various changes may be made in the details of the invention as described herein, without sacrificing any of the advantages thereof, or departing from the scope of the appended claims.

I claim:

1. In a bi-directional stepping mechanism comprising a mainsha-f-t to which is attached a ratchet wheel having twosets of teeth facing in opposite directions and having a pawl for engagement with each set of teeth and a pawl (c) actuation means for each carrying member to cock its pawl on one set of teeth;

(d) said carrying members, pawls and pawl depressors so geometrically arranged that said actuation of the carrying member engages the depressor with the 0pposite pawl moving it out of engagement with the opposite set of teeth; and

(e) means for restoring said pawl carrying member, thereby rotating said ratchet wheel by means of its pawl, and also re-engaging the opposite pawl into an opposing set of teeth.

2. The mechanism of claim 1, wherein the means for actuating each of the pawl carrying members is a solenoid.

3. The mechanism of claim 1, including a detent arm acting against said ratchet wheel.

4. The mechanism of claim 2, wherein said pawl carrying members comprise an armature positioned adjacent 6 each of said actuating means adapted to swing into contact with said solenoid.

5. The mechanism of claim 1 for transporting and sensing perforated tape further including a capstan secured to said shaft and adapted to receive said tape, means on said shaft to grip and advance said tape, and a sensing device adapted to perceive and report the data contained on said tape.

References Cited by the Examiner UNITED STATES PATENTS 2,933,931 4/1960 Lisinski. 3,078,732 2/ 1963 Schaoht. 3,092,296 6/ 1963 Andrews 226-49 M. HENSON WOOD, JR., Primary Examiner.

I. N. ERLICH, Assistant Examiner. 

1. IN A BI-DIRECTIONAL STEPPING MECHANICAL COMPRISING A MAINSHAFT TO WHICH IS ATTACHED A RACHET WHEEL HAVING TWO SETS OF TEETH FACING IN OPPOSITE DIRECTIONS AND HAVING A PAWL FOR ENGAGEMENT WITH EACH SET OF TEETH AND A PAWL DISENGAGING MEANS OPERABLE FOR ONE PAWL WHEN THE OTHER PAWL IS DRIVING THE WHEEL, THE IMPROVEMENT COMPRISING: (A) A PAIR OF PAWL CARRING MEMBERS TO EACH OF WHICH A PAWL IS RIGIDLY ATTACHED; (B) SAID PAWL DISENGAGING MEANS COMPRISING A PAWL DEPRESSOR RIGIDLY ATTACHED TO THE CARRING MEMBER OF THE OPPOSITE PAWL; (C) ACTUATION MEANS FOR CARRING MEMBER TO COOK ITS PAWL ON ONE SET OF TEETH; 